Summary of the invention
The technical problem to be solved in the present invention is, for the defect that above-mentioned filter antenna size is large, structure is compact not of prior art, provides a kind of difference Quasi-Yagi antenna of integrating filtering function.
The technical solution adopted for the present invention to solve the technical problems is: construct a kind of difference Quasi-Yagi antenna of integrating filtering function, comprise substrate, described substrate comprises the upper and lower that consist of microwave-medium substrate, and the intermediate layer consisting of prepreg;
The difference Quasi-Yagi antenna of described integrating filtering function also comprises: director, radiating element, reflector, filter and transition structure;
Wherein, director is printed on the upper strata of described substrate;
Radiating element comprises the first metal portion and the second metal portion that is printed on respectively described substrate the upper and lower;
Reflector is printed on the intermediate layer of described substrate;
Filter assigns between radiating element and reflector;
Described filter comprises two the first resonator and the second resonators that all contain through hole; Through hole runs through the microwave-medium substrate of described substrate the upper and lower and the prepreg in intermediate layer; The first resonator comprises the 3rd metal portion and the 4th metal portion of the upper and lower that are printed on respectively described substrate; The second resonator comprises that the five metals of the upper and lower that are printed on respectively described substrate belongs to portion and the 6th metal portion; The 3rd metal portion of the first resonator is connected by through hole with the 4th metal portion, to realize short circuit; The five metals of the second resonator belongs to portion and is connected by through hole with the 6th metal portion, to realize short circuit;
The distributing point of described the second resonator is connected with the distributing point of radiating element by parallel strips;
Described transition structure is connected with described the first resonator, with by the signal transition in parallel strips to the second microstrip line;
Described transition structure comprises the 7th metal portion and the 8th metal portion that is printed on respectively described substrate the upper and lower.
In one embodiment, described filter is band pass filter.
In one embodiment, described the first resonator and the second resonator are the short circuit resonator of quarter-wave parallel strips form, and are single electric impedance resonator.
In one embodiment, described the second microstrip line is back-to-back microstrip line pair, and it comprises the 9th metal portion and the tenth metal portion that is printed on respectively described substrate the upper and lower, and the 11 metal portion that is printed on substrate intermediate layer.
In one embodiment, the length of described director equals as 1/2nd wavelength in center of antenna frequency; Distance between described radiating element and reflector is quarter-wave.
In one embodiment, described director, radiating element and reflector form original Quasi-Yagi antenna.
In one embodiment, the centre frequency of described filter is 1.81GHz, and relative bandwidth is 5%.
In one embodiment, the length L dir of director is 50mm, and the length L dri of radiating element is 34mm, the distance L between director and radiating element
0for 25mm, the distance L between radiating element and reflector
1for 30mm, the distance L of the second resonator and radiating element
2for 12.6mm, the length L that is connected parallel strips between the distributing point of the second resonator and the distributing point of radiating element
3for 18.3mm, the width W dir of director is 2mm, and the width W dri of radiating element is 2mm, and the width W gnd of reflector is 30mm, the width W that is connected parallel strips between the distributing point of the second resonator and the distributing point of radiating element
0for 0.6mm, the distance g between resonator resonator is 1.57mm, and the distributing point of the first resonator is apart from the distance D of the first resonator left end
0for 2mm, the distributing point of the second resonator is apart from the distance D of the second resonator 142 right-hand members
1for 6mm.
In one embodiment, the second microstrip line is connected with two microstrip lines away from one end of the first resonator, to be connected with sub-miniature A connector; Article two, the width of microstrip line is respectively 1.74mm and 1.8mm.
In one embodiment, the dielectric constant of prepreg is different from the dielectric constant of microwave-medium substrate.
The difference Quasi-Yagi antenna of implementing integrating filtering function of the present invention, has following beneficial effect: in the situation that not increasing antenna original size, integrate filtering and radiation; Compact conformation; There is good cross polarization and lower loss.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing:
Fig. 1 is the structural representation of the difference Quasi-Yagi antenna of the integrating filtering function in one embodiment of the invention;
Fig. 2 is the planar structure schematic diagram of overlooking visual angle of the Quasi-Yagi antenna in one embodiment of the invention;
Fig. 3 is the planar structure schematic diagram of overlooking visual angle of the band pass filter in one embodiment of the invention;
Fig. 4 is that the cross-polarized maximum of difference Quasi-Yagi antenna of the integrating filtering function in one embodiment of the invention and gain are along with the variation tendency comparison diagram of distance between the radiating element of antenna and filter;
Fig. 5 is the cross polarization on E face of the difference Quasi-Yagi antenna of the integrating filtering function in one embodiment of the invention along with the trend comparison diagram that the relative distance at the center of filter and the center of antenna radiation unit changes;
Fig. 6 is that the input impedance of ordering at A point and B of the difference Quasi-Yagi antenna of the integrating filtering function in one embodiment of the invention is along with L
3the trend comparison diagram of variation;
Fig. 7 is that the return loss of difference Quasi-Yagi antenna of the integrating filtering function in one embodiment of the invention is along with D
1the trend comparison diagram of variation;
Fig. 8 is the return loss of difference Quasi-Yagi antenna and the emulation of actual gain and the actual measurement comparison diagram of the integrating filtering function in one embodiment of the invention;
Fig. 9 is emulation and the actual measurement comparison diagram of the antenna pattern on the difference Quasi-Yagi antenna of the integrating filtering function in one embodiment of the invention E face in 1.81GHz frequency;
Figure 10 is emulation and the actual measurement comparison diagram of the antenna pattern on the difference Quasi-Yagi antenna of the integrating filtering function in one embodiment of the invention H face in 1.81GHz frequency.
Embodiment
For technical characterictic of the present invention, object and effect being had more clearly, understand, now contrast accompanying drawing and describe the specific embodiment of the present invention in detail.
It referring to Fig. 1, is the structural representation of difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention.The difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention is three layers of circuit structure.Concrete, the difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention comprises substrate, this substrate comprises upper strata 1 and the lower floor 3 that microwave-medium substrate forms, and the intermediate layer 2 consisting of prepreg.Prepreg is for bonding two-layer microwave-medium substrate.The dielectric constant of prepreg is different from the dielectric constant of microwave-medium substrate.H in Fig. 1
1for the thickness of microwave-medium substrate is the thickness of the upper and lower of substrate, h
2for the thickness of prepreg is the thickness in intermediate layer.
The difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention comprises: Quasi-Yagi antenna, filter 14 and transition structure 15.Quasi-Yagi antenna comprises: director 11, radiating element 12 and reflector 13 (metal ground, in an embodiment of the present invention, metal ground in the reflector as antenna also as difference is micro-with right ground back-to-back).Wherein, director 11 is printed on the upper strata 1 of substrate.Radiating element 12 comprises and is printed on respectively the first metal portion of substrate upper strata 1 and lower floor 3 and the second metal portion (owing to adopting parallel strips differential signal transmission, and parallel strips is levels distribution, so radiating element 12 is divided into the first metal portion and the second metal portion that is printed on respectively substrate upper strata 1 and lower floor 3).Reflector 13 is printed on the intermediate layer 2 of substrate.Filter 14 assigns between radiating element 12 and reflector 13.
Concrete, filter 14 is band pass filter, it comprises two resonators (141,142).These two resonators (141,142) are the short circuit resonator of quarter-wave parallel strips form, and are single electric impedance resonator, and they all contain through hole 4.Through hole 4 runs through upper strata 1, intermediate layer 2 and lower floor 3 (prepreg and the two-layer microwave-medium substrate that run through substrate).Resonator 141 comprises and is printed on respectively the upper strata 1 of substrate and the 3rd metal portion of lower floor 3 and the 4th metal portion.Resonator 142 comprises and is printed on respectively the upper strata 1 of substrate and the five metals of lower floor 3 belongs to portion and the 6th metal portion.The 3rd metal portion of resonator 141 is connected by through hole 4 with the 4th metal portion, to realize short circuit; The five metals of resonator 142 belongs to portion and is connected by through hole 4 with the 6th metal portion, to realize short circuit.
Transition structure 15 is connected with the distributing point of resonator 141, take the signal on back-to-back the second microstrip line 5 by the signal transition in parallel strips.Then, recycle a pair of back-to-back microstrip line and carry out differential feed.Concrete, transition structure 15 is printed on respectively the 7th metal portion and the 8th metal portion of substrate upper strata 1 and lower floor 3.The distributing point of resonator 142 is connected with the distributing point 121 of radiating element 12 by parallel strips 6; The distributing point of resonator 141 is connected with a pair of back-to-back the second microstrip line 5, and the second microstrip line 5 is connected with two microstrip lines away from one end of the first resonator 141, to be connected with sub-miniature A connector.The second microstrip line is back-to-back microstrip line pair, and it comprises the 9th metal portion and the tenth metal portion that is printed on respectively substrate upper strata 1 and lower floor 3, and the 11 metal portion that is printed on substrate intermediate layer 2.
The difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention, on the basis of original Quasi-Yagi antenna, design a load and be the band pass filter of 100 ohm, again by filter co-design together with antenna, in design process, need to consider circuit performance and the radiance of the difference Quasi-Yagi antenna of this integrating filtering function simultaneously.The difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention, not increasing the size of original Quasi-Yagi antenna and not changing on the basis of original Quasi-Yagi antenna radiance, can obtain better frequency selectivity.
In an embodiment of the present invention the number of director is not restricted.
In an embodiment of the present invention, the each several part of the difference Quasi-Yagi antenna of integrating filtering function is printed on each layer of substrate, and need to be fixed its position according to the design standard of antenna.Below with reference to a concrete design standard, the position relationship of the each several part of the difference Quasi-Yagi antenna of integrating filtering function is described.
Referring to Fig. 2, the centre frequency of supposing the difference Quasi-Yagi antenna of integrated filter function is f
0(being the centre frequency of filter 14), wavelength X=Cf
0(C is 3 * 10
8m/s).The length L dir of director 11 is approximately equal to 1/2nd wavelength, the length L dri of radiating element 12 equals quarter-wave (length of two metal portions of radiating element 12 and be approximately equal to 1/2nd wavelength), the length of reflector 13 is approximately equal to 1/2nd wavelength, the distance L between radiating element 12 and reflector 13
1be approximately equal to quarter-wave.
Referring to Fig. 3, in the difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention, filter 14 (for band pass filter) utilizes parallel strips to realize, the resonator of two terminal shortcircuit (141,142) be by the metal that is positioned at the upper and lower with for being connected the through hole of the metal of the upper and lower, form.After the design standard (centre frequency and relative bandwidth) of filter 14 is determined, according to this design standard, can obtain the coupling matrix of filter 14 (band pass filter of symmetrical configuration).According to coupling matrix, the external sort factor (Q of filter 14
e) and coupling coefficient (k
12) can through type (1) and formula (2) determine:
formula (1)
Formula (2)
Referring to Fig. 3, the distributing point of resonator 142 is apart from the distance D of resonator 142 right-hand members
1(or the distributing point of resonator 141 is apart from the distance D of resonator 141 left ends
0), the distance g between resonator 141 resonator 142 affects Q
eand k
12factor.Setting Q
eand k
12situation under, by regulating D
0(or D
1) and g can realize Q
eand k
12meet.
The position of filter 14 has a certain impact (for example, impact gain and cross polarization) to the radiation characteristic of the difference Quasi-Yagi antenna of integrating filtering function, and this is because intercoupling between filter and Quasi-Yagi antenna produces.Therefore, the position of filter 14 in the difference Quasi-Yagi antenna of integrating filtering function should first be determined, after the position of filter 14 is fixing, regulates the input impedance of Quasi-Yagi antenna and on resonator 141, select a suitable distributing point to realize impedance matching by going.
Referring to Fig. 4 and Fig. 5, cross polarization and considering of gain by antenna can obtain a suitable L
2the value of the distance of radiating element 12 (resonator 142 with) and d (d be in the y-direction the relative distance at the center of filter and the center of radiating element).Just be fixed up in the position of filter 14 so, now for the difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention, need one section of parallel strips to remove to connect Quasi-Yagi antenna (in an embodiment of the present invention, the Quasi-Yagi antenna that is that only comprises director 11, radiating element 12 and reflector 13) and filter, the now input impedance of Quasi-Yagi antenna has become the input impedance of seeing into from B point as shown in Figure 1, and they are different from the input impedance of seeing into from A point.Therefore need to be adjusted in the position of distributing point on resonator 142 is D
1value come and the input impedance coupling of new antenna, and regulate D
1value can bring L
3faint variation, this can bring the change of the input impedance of the Quasi-Yagi antenna of seeing into from B point simultaneously.As shown in Figure 6, L
3variation very faint to the change of the input impedance of the Quasi-Yagi antenna of seeing into from B point.Therefore can be, D by being adjusted in the position of distributing point on resonator
1value come and the input impedance coupling of new antenna, as shown in Figure 7, D
1change larger to the return loss effects of system, this is because D
1variation caused the change of the external sort factor of resonator 2.
Preferably, if Quasi-Yagi antenna is original Quasi-Yagi antenna (be prior art, the present invention does not describe this), the design standard of filter 14 is centre frequency (f
0) be that 1.81GHz and relative bandwidth (FBW) they are 5%, pass through the optimization to the size of integrally-built each several part, size and the position of each part of difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention are as follows: Ldir=50mm, Ldri=34mm, L
0=25mm, L
1=30mm, L
2=12.6mm, L
3=18.3mm, Wdir=Wdri=2mm, Wgnd=30mm, W
0=0.6mm, W
1=1.74mm, W
2=1.8mm, g=1.57mm, D
0=2mm and D
1=6mm.Wherein, Ldir is the length of director 11, and Ldri is the length of radiating element 12, L
0for the distance between director 11 and radiating element 12, L
1for the distance between radiating element 12 and reflector 13, L
2for the distance of resonator 142 with radiating element 12, L
3for the length that is connected microstrip line 6 between the distributing point of resonator 142 and the distributing point of radiating element 12, Wdir is the width of director 11, and Wdri is the width of radiating element 12, and Wgnd is the width of reflector 13, W
0be the width that is connected parallel strips between the distributing point of the second resonator and the distributing point of radiating element, W
1and W
2be respectively microstrip line 6 and diverge to the width (W of two microstrip lines of formation
1, W
2be the size of initial feeder line, and microstrip line 6 diverges to, to form two microstrip lines be to connect SMA connector when testing), g is the distance between resonator 141 resonator 142, D
0for the distributing point of resonator 141 distance apart from resonator 141 left ends, D
1for the distributing point of resonator 142 distance apart from resonator 142 right-hand members.
Use software HFSS and Agilent E5230C network analyser and microwave dark room that the difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention is simulated and measured, the result of measuring as Figure 8-Figure 10, the centre frequency that can see the difference Quasi-Yagi antenna of integrating filtering function of the present invention is 1.81GHz, FBW is 5%, maximum be respectively-the 22dB of its cross-polarization levels on E face and H face and-17dB, therefore the difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention is not in the situation that increase the size of Quasi-Yagi antenna own and make it not only possess good radiance also to possess filtering performance simultaneously, therefore realize to a certain extent comparatively compact structure, and there are good cross-polarization levels and good frequency selectivity.
The design standard difference that should be understood that the difference Quasi-Yagi antenna of integrating filtering function, the position relationship of its each several part is not identical, for example, if frequency (f centered by the design standard of antenna
0) for 1.81GHz and relative bandwidth (FBW) are 10%, in the size and location parameter of each part of the difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention, g=0.6mm, D
0=4.8mm, D
1=9.6mm, the design standard of other size and above-mentioned antenna is centre frequency (f
0) for 1.81GHz be the same (above-mentioned Ldir=50mm, Ldri=34mm, L while being 5% with relative bandwidth (FBW)
0=25mm, L
1=30mm etc.).
The difference Quasi-Yagi antenna of the integrating filtering function of the embodiment of the present invention, in the situation that not increasing antenna original size, integrates filtering and radiation; Compact conformation; There is good cross polarization and lower loss.
In description of the invention, it will be appreciated that, term " first ", " second ", " the 3rd " etc. are only for describing object, and can not be interpreted as indication or hint relative importance.
By reference to the accompanying drawings embodiments of the invention are described above; but the present invention is not limited to above-mentioned embodiment; above-mentioned embodiment is only schematic; rather than restrictive; those of ordinary skill in the art is under enlightenment of the present invention; not departing from the scope situation that aim of the present invention and claim protect, also can make a lot of forms, within these all belong to protection of the present invention.